A variety of techniques are known for interactive exchange of a variety of information using devices such as, for example, mobile phones or portable game devices that communicate with each other over a wired or wireless connection.
Typical examples include participating in a game over a network. In such a game, a plurality of communication devices are connected over a network, and a variety of services that would be impossible with only one device are provided, for example allowing a plurality of users to compete or cooperate.
A communication system that uses such a network is not limited to games and is attracting attention from businesses in all fields as a possible medium for providing a variety of new services. One example of a proposed technique to allow for such services is an entertainment system that is not limited to network gaming but can also provide marketing or advertisement information (for example, see JP2002-049681A (Patent Literature 1)).